Stabilization of emulsions sensitized with alkylene oxide polymers



United States Patent No Drawing. Application November 8, 1952,

Serial No. 319,614 i 24 Claims. I (21. 95-7 This invention relates to fog-inhibiting agents and stabilizers for photographic emulsionsand to photographic emulsions containing them.

It is known that photographicemulsions, particularly ultra-sensitive emulsions or those containing optical sensitizers exhibit a tendency to form a deposit of silver in the emulsion upon development. This deposit extends more or less uniformly over the entire emulsion and is known as fog. Photographic fog is of two types: local and'general. Local fog is formed by exposure of the film or plate at undesired points as by a light leak in the camera. General fog is formed in a number of ways. It may be caused by the conditions of high temperature or humidity or unusuallylong time of storage. The nature of the emulsion may also produce chemical fog as well as the conditions of development of the emulsion as by development for protracted periods of time or'at temperatures above normal. We are primarily concerned with fog and sensitivity changes in photographic films produced by storage under adverse conditions of temperature and humidity or for prolonged periods of time before exposure and development. v

General fog and loss of sensitivity of the emulsion are especially likely to occur when the sensitive material is stored under conditions other than ideal, that is, under conditionsof high temperature and humidity, as in tropical regions. 7 d

It is known that the effective sensitivity of photographic silver halide emulsions may be increased by adding to them derivatives of alkylene oxides such as ethylene oxide polymers having molecular weights of 300 or more. Thepractical value of these compounds is severly limited by their tendency to increase fog on storage of the photographic film, especially storage at elevated temperatures and-'humidities. It has been found diificult to control this by the antifoggants commonly available without using quantities of antifoggant which partly neutralize the speed increase obtained from the alkylene oxide derivatives. It is therefore an object of the. present inventionjto provide a method for stabilizing photographic emulsions sensitized with alkylene oxide derivatives suchas polyethylene oxides. A further object is to provide a means for reducing the fog produced upon keeping of emulsions so sensitized, especially emulsions stored under tropical or other adverse conditions. A still further object is to provide a means for stabilizing the speed and contrast of emulsions so sensitized. Other objects will appear from the following description of my invention. t

These objects are accomplished in general byadding to the emulsion sensitized with alkylene oxide polymers, certain organiccompounds of mercury in which the mermercuric or mercurous salts ofv an inorganic or organic acid.

The alkylene oxide polymers used to sensitize the emul sions may be of various types. The alkylene oxidesfrom" which the polymers are derived contain from 2 to 4 carbon atoms, e. g., ethylene oxide, propylene oxide and cury atom has at least one ionizable bond, or simple "ice ' scribed in U. S. Patents 2,423,549 and 2,441,389. I

Various derivatives of alkylene oxides may also be used to sensitize the silver .halide emulsions, e. g., condensation products of alkylene oxide with glycols, such as those having from 8 to ,18 carbon atoms as described in U. S. Patent 2,240,472 and British Patent 443,559, as well as condensation products of alkylene oxides with aliphatic alcohols, aliphatic acids and aliphatic amines, that is, polyalkylene ethers, esters and amides, the preparation of which is described in U. S. Patent 1,970,578, and condensation products of alkylene oxides with hexitol ring dehydration products, as described in U. S. Patent 2,400,532.

In each case the polyalkylene oxide or derivative of alkylene oxide should have a molecular weight of at least 300 and, preferably a molecular weight of 1500 to 4000 or more. i

The compounds of mercury used to stabilize emulsions sensitized with the polyalkylene oxides are of three types: (1), molecular compounds of mercuric salts with amines or salts of amines, (2) organic compounds of mercury'in which the mercury atom is attached by a non-ionic or covalent bond to an organic nucleous,.especially a heterocyclic organic nucleus, and by) an ionic or electrovalent bond to an anion, and (3') simple salts of mercury with organic or inorganic acids: 3

The principal purpose 'of my invention isto provide a means for maintainingthe sensitivity and fog of silver halide emulsions at or. close to initial optimum values under keeping conditions of high temperature and humidity. Preferably, the fog inhibitors which I propose to use are added to the emulsion at any stage during the process of manufacture prior to coating the emulsion. The mercury fog inhibitor may be addedto the emulsion insolution in any convenient solvent not injurious to the emulsion such as water, lower alcohols and ketones. 7" A solution of the mercuric compound which I employ when added in suitable concentration before coating to unsensitized or optically sensitized silver halide emulsions usually does not appreciably affect the sensitivity and fog when measurements are made soon after coating. However, when sensitometric measurements are made after appreciable intervals of time under tropical or dry conditions of storage at elevated temperatures, these compounds do stabilize speed and maintain fog at a low level.

Any of the mercuric compounds disclosed in Allen, Byers and Murray U. S. application Serial No. 319,611, filed concurrently herewith, may be used to stabilize the emulsions according to my invention; The following is typical:

Bis(2-amino-5-iodopyridine hydriodide) mercuric iodide Any of the mercuric compounds disclosed in Leubner and Murray U. S. application Serial No. 319,613, filed concurrently herewith, may also be used. The following is typical:

Z-pyridyl mercuric chloride with ,gelatino-silver bromoiodide emulsions.

Any of the compounds disclosed in Carroll and Murray U. S. application Serial No. 319,612, filed concurrently herewith may also be used. These compounds include mercuric and mercurous chloride, bromide and iodide, mercuric acetate, mercuric nitrate, mercurous sulfate, etc. 1

The alkyleneoxide derivatives used to sensitize the emulsions may be illustrated by the following specific examples, although my invention is in noway limited to the use of these specific compounds.

HOCHgCHzO(CHzCH O),.CH1OHzOH Polyethylene oxide O(CHQG HzO)nCH1CHzQH (C rho owmcmommcmon ,Di- (polyethylene-glycoxy) -deca ne HO GHQGHZO (CHzCHzOhC HgCHzO CflHzz Polyethylene oxide oleyl ether where n=an integer greater than about 10.

The preparation of silver halide emulsions involves three separate operations: (1) the emulsification and digestion or ripening of the silver halide, (2) the freeing of the emulsion from aqueous soluble salts usually by washing, (.3).the second digestion or after-ripening to obtain increased sensitivity (Mees, The Theory of the Photographic Process, 1942, page 3). The fog inhibit ing agents may be'added at any stage, e. g., after the final digestion.

The photographic emulsions which I use are of the developing-out type and best results have been obtained However, emulsions of varying halide content may be used.

The emulsions may be chemically sensitized by any of the accepted procedures, in additionto or 'in combination with the sensitizing with alkylene oxide polymers. The emulsions may'be digested with naturally active gelatin, or sulfur compounds may be added such as those described in Sheppard U. S. Patent 1,574,944 and 1,623,499, and Sheppard and Brigham U. S. Patent 2,410,689.

The emulsions may also be treated with salts of the noble metals 'such' as ruthenium, rhodium, palladium, iridium and platinum, all of which belong to group VIII of the periodic table of elements and have an atomic weight greater than 100. Representative compounds are ammonium chloropalladate, potassium chloroplatinate and sodiumchloropalladite, which are used for sensitizing .in amounts below that which produces any substantial fog inhibition, as described in Smith and Trivelli U. 5. Patent 2,448,060, and as antifoggants in higher amounts, asdescribed in Trivelli and Smith U. S. Patents 2,566,245 and 2,566,263.

The emulsions may also be chemically sensitized with gold salts as described in Waller and Dodd U. S. Patent 2,399,083, Damschroder U. '5. Patent 2,597,856, and Yutzy and Leermakers 'U. S. Patent 2,597,915. Suitable compounds are potassium chloroaurite, potassiumauritb iocyanate, potassium chloroaurate, auric trichloride and 2-aurosulfobenzothiazole methochloride.

The emulsions may also be chemically sensitized with reducing agents such as stannous salts (Carroll U. S. Patent 2,487,850), polyamines such as diethylene triamine (Lowe .and Jones U. S. Patent 2,518,698), poly- 2,521,925), or bis-(p-aminoethyl) sulfide and its watersoluble salts (Lowe and Jones U. S. Patent 2,521,926).

The sensitizing and stabilizing combinations of polyalkylene oxides and the mercuric compounds are efiective in the presence or absence of optical sensitizing dyes. Since optical sensitizing may aifect stability of emulsions with respect to sensitivity, fog and latent image changes, the action of the compounds of this invention is not completely independent of optical sensitizing or other emulsion variables. I have found, however, that both unsensitized emulsions and emulsions sensitized with cyanine or merocyanine dyes or both may be treated with polyalkylene oxides and mercuric compounds according to my invention.

The most useful concentration of the mercuric compound in the emulsion is from about 0.05 mg. to 1.0 mg. per gram mole of silver halide in the emulsion. Although higher amounts may be used, I have found that no emulsion is likely to tolerate as much as 5 times this upper limit without serious desensitization. Optimum concentrations are about 0.5 mg. per gram mole of silver halide for the molecular compounds of mercuric .salts with amines or salts of amines, about 0.1 mg. per gram mole of silver halide for the organic compounds of .mercury in which the mercury atom is attached by a nonionic bond to an organic nucleus and by anionic bond to an anion, and from 0.05 mg. to 0.5 mg. for the simple mercuric salts such as mercuric chloride and mercuric iodide.

The stabilizing action was determined by incubation of the emulsions, usuallyfor one week at 120 F. and 20% relative humidity,.unless otherwise stated in the examples. The results of aging tests .are tabulated below and compare speed, gamma and fog of the emulsions with and without the stabilizing compound.

Example 1 One liter of a negative speed gelatino-silver bromoiodide emulsion containing 0.24 mole of silver halide per liter was digested with a sulfur compound such as disclosed in Sheppard U. S. Patent 1,574,944 and potassium chloroaurate and'optically sensitized in the conventional manner. To a portion of the emulsion there was added 52.5 grams per gram mole of silver halide of a polyethylene oxide having a molecular weight of 300, and to a portion of this emulsion there was also added -0.7 mg. per gram mole of silver halide of bis-(2-amino-5-iodopyridine hydroiodide) mercuric iodide.

The emulsions were coated on film base and were exposed on an Eastman type IbSensitometer and developed for 8 minutes at 68 F. in a developer of the following formula:

Water to 1 liter.

The films with and without the various addenda were held at 120 F. and 20% relative humidity for one week and were then exposed and developed as indicated. The results of tests for "speed, gamma and fog were as follows:

amines such as spermine (Lowe and Allen U. S. Patent Agent Fresh Test Alter Incubation "Compound 32 gm. Speed Gamma Fog Speed Gamma Fog (I) Polyethylene glycol 300"--- 62.131 1,320 1.41 .09 2,200 1.21 .47

I+Bis- (2 -amino -5 -.lodopyridine I hydrlodide).mereurlc10d1de.-. 0.2 1,100 1.31 .06 2,150 1.44 .21

with a sulfur compoundsuch as disclosed in Sheppard U. S. Patent 1,574,944 and potassium chloroaurate, and

emulsion was divided into several portions and to some of these were added a polyethylene oxide having a molecular weight of about 4000 (Carbowax 4000), and the mercuriccompounds shown in the tablebelow. Each optically sensitized with a mixture of cyanine dyes in the 5 g gg g i g z i g g tllle g f' conventional way. To portions of the emulsion the mer- E i ens x 25 ope 0 3 f curic compound bis-(Z-aminoJ-iodopyridine hydroio n a e oper e owmg comp $1 G dide)mercuric iodide'was added in varying amounts and N th 1 h L 1 if i to other portions of the emulsion the mercuric compound g eno Su ate a was added togetherwith the condensation product of 1 10 'i- -"a mole of oleyl alcohol with approximately moles of i es1ccateh)5 56 ethylene oxide. Upon incubation of samples of the emulf mono y rate sions as indicated in the table, and measurement of i .5 e 5 speeds as E where E is the exposure in meter-candle- 15 3 er 0 1 seconds of approximately sunlight distribution required Upon testing for speed, gamma and fog, before and to produce a density of 0.20 above fog, the following reafter incubation as in Example 1, the following results suits were obtained upon development for 6.5 minutes in were obtained:

7 Fresh Test After Incubation 7 Compound mg./mole Speed Gamma Fog Speed Gamma Fog Control 105 1.38 .07 165 1.27 .10 (I) With Carbowax4000- 600 280 1.34 .10 240 1.34 .14 1+(2-amino-5-iodopyridine),-

HI-Hgn 0.0 235 1.35 .00 210 1.43 .11 I+Mercu1icchloride.. .06 235. 1.40 .10. 240 1.35 .12 Do .15 215 1.39 .00' 220 1.30 .12 I+Pyridylmereuric chloride... 0.6 205 1.34 .10 220 1.39 .12

adeveloper of the following composition: E l 4 Water -1 ce 750 A medium speed. gelatino-silver bromoiodide emulsion N-methyl-p-aminophenol sulfate grams 2 was sensitized with a mixture of gold andusulfur com- Hydroquinone d0 5 pounds as in Example 2, and divided into two portions. Sodium sulfite (desiccated) do 100 To one portion of this emulsion there was added a mix- Borax (granular) do .2 ture of the reduction sensitizer triethylene tetramine Water to 1 liter. (U. S. Patent 2,5l8,698) and a polyethylene oxide hav- Sensitivitty 51%" hi I wee a Original Sensitivity packages sealed at Compound mg./mole 74 F., 54% RH Speed Gamma Fog Speed Gamma Fog Control 7,050 0.82 0.10 7,050 0.75 0.12 (A) Bis(2-m:nino-5-iodopyri- V dine hydroiodide)mercuric 10am 0.56 7,200 0.70 0.09 7,350 0. 75, 0.11 D 0.80 0,900 0.79 0.09 4,850 0.75 0.10 1.1 5,700 0.07 0.08 7,200 0.76 0.08 Control-.- 7, 200 0.70 0.10 0, 700 0.71 0.13 (B) Condensation roduet of v oleyl alcohol wi ethylene oxide 280 11,100 0.78 0.12 8,050 0. 75 0.20 0.56 10,200 0.76 0.12 11,700 0.78 0.14 0 80 10,200 0.73 0.12 12,800 0.72 0.13 11 10,400 0.30 0.10 12,800 0.85 0.10

Example 3 A medium speed glatino-silver bromoiodide emulsion was sensitized with a mixture of gold and sulfur compounds as in Example 2, and was then digested to optimum speed in the presence of a reduction sensitizer of the type disclosed in my U. S. Patent 2,487,850. This ing amolecular weight of about 4000 (Carbowax 4000). To separate portions of the emulsion sensitized in this way, there were added the mercuric compounds shown in the table below. Each of these emulsions was-exposed, developed and tested as in Example 3, with the following results:'

Fresh Test After Incubation Compound mgJmole Speed Gamma Fog Speed Gamma Fog Control 250 1.40 .00 255 1. .12

(I) i i h l t tr 36 re ene e amme oarbogax-m 60o 400 1.80 .18 440 1.30

1+(2-amino-5-iodopyridineh' 1. r, 0 a 400 1.87 .10 550 1.34 .32 Do 1 2 235 1.92 .10 315 1.60 .09 l-l-Mercuric chloride .12 370 1.91 .14 530 1. 87 .34 I+Pyridyl mercuric chloride... 0. 6 400 1. 87 16 540 1. 29 32 Control. 240 1. 66 11 310 1. 36 14 7 Example A negative-speed gelatino-silver brornoiodide emulsion was chemically sensitized with sulfur and gold sensitizers as in Example 2 and was digested to optimum speed and divided into two portions. To one portion of this emulsion there was added a polyethylene oxide having a molecular weight of about 4000 (Carbowax 4000). To separate portions of the emulsion sensitized in this way, there were added the mercuric compounds shown in the table below. Each of the emulsions was exposed on a Ib sensitometer and developed for 5 minutes in a developer of the following composition:

was sensitized in the same way as described in Example 2. To a portion of this emulsion there was added a mixture of polyethylene glycol oleyl ether and KzI-Ig( CN) in varying amounts. .To another portion of the emulsion there was added a mixure of polyethylene glycol cetyl ether and K2Hg(CN). All .of these portions were coated and emulsions with and without the addenda were exposed and developed in the same way .as described in Example 2, before and after incubation for 7 days at 120 P. All exposures were made on a Ib Sensitometer. Upon testing for speed, gamma and fog the following results were obtained:

Fresh Test After Incubation Compound mgJmole Speed Gamma "Fog Speed Gamma Fog go m r- 3,500 0.73 0.01 2,550 0.08 0.10

oye YGDGQYOOOG e e. 1 i i i f 1 f M }4,750 0.73 0.01 5,100 0.75 0.00

oye yenegyco oey ether. 0 l g h l 80% }4,350 0.77 0.02 5,100 0.75 0.02

oye y 8119 KHQCNM M5 }4,750 0.15 0.01 5,850 0.70 0.03

Grams Example 8 N-methyl-p-aminophenol sulfate 2.5 Hydroquinone 2.5 A medium-speed gelatino-silver bromoiodide emulsion Sodium sulfite, desiccated Sodium metaborate Potassium bromide Water to 1 liter.

30 was sensitized with 20 mgs. per mole of silver halide of polyethylene oxide having a molecular weight .of about 4000 (Carbowax 4000 and to other portions were added the polyethylene oxide 'and'varying amounts of Fresh Test After Incubation Compound mgJmole Speed Gamma Fog Speed Gamma Fog Control 5, 900 0. 83 .08 3,000 0. 89 21 (I) With Carbowax 4000 500 8, 800 0. 82 08 3, 800 0.75 .27

1+ (2-amino-5-iodopyridlneh- HI-HgIa 1.0 8, 200 0. 82 0. 7 3, 550 0.87 11 I+Merourlc todid 25 7, 400 0. 0. 8 4, 800 0. 72 20 Do 1.0 6, 0. 88 0.0 3,200 0. 82 .06

Example 6 8-chloromercuriquinoline, as shown in the following In order to illustrate the action of the mercury antifoggants on an emulsion containing both a polyethylene oxide and a chloropalladate, an emulsion of the typeused 50 in Example 5 was treated with these agents as shown in the table below, and processed as described in Example 5. The following results were obtained:

-.tion as that shown in Example 3.

table. These emulsions were coated on a cellulose ace- .tate support, exposed on a 'Ib Sensitometer and developed for 3 minutes in a developer having the same composi- Upon incubation of each of the coatings-for two weeks at F. and-testing Fresh Test Alter Incubation Compound mgJmole Speed Gamma Fog Speed Gamma Fog Ammonium ehloropalladate 500 3, 800 0. 96 10 2,950 0.84 16 mFirrinnonium ,chloropalla- 500 a e p +Oarbowax 4000 500 }4,200 0.94 .12 is, 200 0. so .20 I-l-(Z-amlno B-iodopyrl EI-HgIz 1. 0 3, 300 0. 96 12 4, 0. 72 08 I-i-Merem'lc iodl 0. 25 2, 950 1. 0 10 4, 750 0. 74 08 Example 7 both sets of coatings for speed, gamma and fog, the fol- A negative-speed gelatino-silver bromoiodide emulsion lowing results were obtained:

Instead of incorporation in. thesilver halide emulsion the fog-inhibitors of my invention may be incorporated in a colloid layer such as a gelatin layer on one or both sides of the film or they maybe incorporated in a processing bath such as a developer or pre-bath. v p,

The fog-inhibiting agents which I'have described may be used in various kinds of photographic emulsions. In addition to being useful in ordinary non-sensitized emulsions they'may also be used in orthochromatic, panchromatic and'X-ray emulsions. If used with sensitizing dyes, they may be added to the emulsion before or after the dyes are added. Various silver saltsmay be used as the sensitive salt, such as silver bromide, silver iodide, silver chloride or mixed silver halides. The mercury compounds and alkylene oxide polymers may be used in emulsions intended for color photography, for example, emulsions containing colorforming couplers, or emulsions to be developed by solutions containing couplers.

The dispersing agents may be gelatin or other colloid such as collodion, albumen, cellulose derivatives or synthetic resins.

It will be understood that I contemplate as included within my invention all modifications and equivalents falling within the scope of the appended claims.

What I claim is:

1. A light-sensitive silver halide emulsion sensitized with an alkylene oxide polymer selected from the class consisting of 1) polyalkylene glycols, (2) condensation products of alkylene oxide with glycols, (3) condensation products of alkylene oxide with aliphatic compounds selected from the class consisting of alcohols, acids and amines and (4) condensation products of alkylene oxide with hexitol ring dehydration products, said alkylene oxide containing from 2 to 4 carbon atoms and said alkylene oxide polymer having a molecular weight of at least 300, said emulsion containing a small amount of a mercury compound selected from the class consisting of (1) a molecular addition compound of a mercury salt with a nitrogen compound of the class consisting of heterocyclic nitrogen compounds in which at least three bonds of the heterocyclic nitrogen atom are attached to carbon, amine-substituted mononuclear aromatic compounds in which three bonds of the amino nitrogen atom are attached to carbon, their halogen acid salts, and the halogen acid salts of aliphatic amines containing at least three carbon atoms, (2) organic compounds of mercury in which the mercury atom is attached by a non-ionic mercury to carbon bond to a cyclic organic nucleus and by an ionic bond to an anion, and (3) simple salts of mercury with organic and inorganic acids.

2. A light-sensitive silver halide emulsion sensitized with an ethylene oxide polymer having a molecular weight of at least 300, said emulsion containing a small amount of a molecular compound of a mercuric salt with a halogen acid salt of a primary amine substituted heterocyclic nitrogen compound.

3. A light-sensitive silver halide emulsion sensitized with an ethylene oxide polymer having a molecular weight of at least 300, said emulsion containing a small amount of an organic compound of mercury in which the mercury atom is attached by a nonionic mercury to carbon bond to a cyclic organic nucleus and by an ionic bond to an anion.

4. A light-sensitive silver halide emulsion sensitized with an ethylene oxide polymer having a molecular weight of at least 300, said emulsion containing a small amount of a simple salt of mercury with an inorganic acid.

5. A light-sensitive silver halide emulsion sensitized with a polyethylene glycol having a molecular weight of at least 300, said emulsion containing a small amount of a molecular compound of a mercuric salt with a halogen acid salt of a primary amine substituted heterocyclic nitrogen compound.

6. A light-sensitive silver halide emulsion sensitized with a polyethylene glycolhaving a molecular weight of at least 300, said emulsion containing a small amount of an organic compound of mercury in which the mercury atom is attached by a non-ionic mercury to carbon bond to a cyclic organic nucleus and by an ionic bond to an anion.

7. A light-sensitive silver halide emulsion sensitized with a polyethylene glycol having a molecular weight of atleast 300, said emulsioncontaining a'small amount of a simple salt of mercury with an inorganic, acid.

8. A light-sensitive sulfur sensitized silver halide emulsion additionally sensitized with an ethylene oxide'polymer selected from the class consisting of (1) polyethylene glycols, (2) condensation products of ethylene oxide with glycols, (3) condensation products of ethylene oxide with aliphatic compounds selected from the class consisting of alcohols, acids and amines,- and (4))condensation products of ethylene oxide with hexitol ring dehydration products, said ethylene oxide polymer having a molecular weight of at least 300, said emulsion containing a small amount of a mercury compound selected from the class consisting of (1) a molecular addition compound of a mercury salt with a nitrogen compound of the class consisting of heterocyclic nitrogen compounds in which at least three bonds of the heterocyclic nitrogen atom are attached to carbon, airline-substituted mononuclear aromatic compounds in which three bonds of the amino nitrogen atom are attached to carbon, their halogen acid salts, and the halogen acid salts of aliphatic amines containing at least three carbon atoms, (2) organic compounds of mercury in which the mercury atom is attached by a non-ionic mercury to carbon bond to a cyclic organic nucleus and by an ionic bond to an anion, and (3) simple salts of mercury with organic and inorganic acids.

9. A light-sensitive sulfur sensitized gelatino-silver halide emulsion additionally sensitized with a polyethylene glycol having a molecular weight of at least 300, said emulsion containing a small amount of a molecular compound of a mercuric salt with a halogen acid salt of a primary amine substituted heterocyclic nitrogen compound.

10. A light-sensitive sulfur sensitized gelatino silver halide emulsion additionally sensitized with a polyethylene glycol having a molecular weight of at least 300, said emulsion containing a small amount of a molecular compound of bis-(Z-amino-S-iodopyridine)hydroiodide mercuric halide.

11. A light-sensitive sulfur sensitized gelatino-silver halide emulsion additionally sensitized with a polyethylene glycol having a molecular weight of at least 300, said emulsion containing a small amount of an organic compound of mercury in which the mercury atom is attached by a non-ionic mercury to carbon bond to a cyclic organic nucleus and by an ionic bond to an anion.

12. A light-sensitive sulfur sensitized gelatino-silver halide emulsion additionally sensitized with a polyethylene glycol having a molecular weight of at least 300, said emulsion containing a small amount of a simple salt of mercury with an inorganic acid.

13. A light-sensitive sulfur sensitized gelatino-silver halide emulsion additionally sensitized with polyethylene glycol oleyl ether and containing a small amount of a molecular compound of a mercuric halide with a halogen acid salt of a primary amine substituted heterocyclic nitrogen compound.

14. A light-sensitive sulfur sensitized gelatino-silver halide emulsion additionally sensitized with a polyethylene glycol having a molecular weight of approximately 4000, said emulsion containing a small amount of a his (2-amino-5-iodopyridine) hydroiodide mercuric halide.

15. The emulsion of claim 8 which is additionally chemically sensitized with gold salts.

16. The emulsion of claim 9 which is additionally chemically sensitized with gold salts.

1?. "[he emulsion of claim 10 which is additionally chemically sensitized with gold salts.

18. The emulsion of claim 14 which is additionally chemically sensitized with gold salts.

19. The emulsion of claim 1 which is additionally chemically sensitized with reduction scnsitizers.

'20. The emulsion of claim 8 which is additionally chemically sensitized with reduction sensitizers.

2luT-he emulsion of claim 10 which is additionally chemically sensitized with reduction sensitizers.

22. The emulsion of claim 8 which is additionally chemically sensitized with gold salts and reduction sensitizers.

'23. The emulsion of claim I i-which is additionally chemically sensitized with goldsalts and reduction sensitizers;

24. The emulsion of claim 12 which is additionally chemioall-ysensitized with gold salts and reduction sensitizersi 1 References Cited in the file of this patent 'UNlIED STATES PATENTS Ftanken u g r e a1. D 1 29 Kankelwitz Nov. 3, 1936 Swan Apr. 29, 1941 Blake et a1. May '21, 1946 Blake July 8, 1947 Blake May 11, 1948 Carroll Nov. 15, 1949 Baldsiefen Feb. 6, 1951 FOREIGN PATENTS 1 Great Britain Dec. 12, 1949 

1. A LIGHT-SENSITIVE SILVER HALIDE EMULSION SENSITIZED WITH AN ALKYLENE OXIDE POLYMER SELECTED FROM THE CLASS CONSISTING OF (1) POLYALKYLENE GLYCOLS, (2) CONDENSATION PRODUCT OF ALKYLENE OXIDE WITH GLYCOLS, (3) CONDENSATION PRODUCTS OF ALKYLENE OXIDE WITH ALIPHATIC COMPOUNDS SELECTED FROM THE CLASS CONSISTING OF ALCOHOLS, ACIDS AND AMINES AND (4) CONDENSATION PRODUCTS OF ALKYLEND OXIDE WITH HEXITOL RING DEHYDRARTION PRODUCTS, SAID ALKYLENE OXIDE CONTAINING FROM 2 TO 4 CARBON ATOMS AND SAID ALKYLENE OXIDE POLYMER HAVING A MOLECULAR WEIGHT OF AT LEAST 300, SAID EMULSION CONTAINING A SMALL AMOUNT OF A MERCURY COMPOUND SELECTED FROM THE CLASS CONSISTING OF (1) A MOLECULAR ADDITION COMPOUND O A MERCURY SALT WITH A NITROGEN COMPOUND OF THE CLASS CONSISTING OF HETEROCYLIC NITROGEN COMPOUNDS IN WHICH AT LEAST THREE BONDS OF THE HETEROCYCLIC NITROGEN ATOM ARE ATTACHED TO CARBON, AMINE-SUBSTITUTED MONONUCLEAR AROMATIC COMPOUNDS IN WHICH THREE BONDS OF THE AMINO NITROGEN ATOM ARE ATTACHED TO CARBON, THEIR HALOGEN ACID SALTS, AND THE HALOGEN ACID SALTS, OF ALIPHATIC AMINES CONTAINING AT LEAST THREE CARBON ATOMS, (2) ORGANIC COMPOUNDS OF MERCURY IN WHICH THE MERCURY ATOM IS ATTACHED BY A NON-IONIC MERCURY TO CARBON BOND TO A CYCLIC ORGANIC NUCLEUS AND BY AN IONIC BOND TO AN ANION, AND (3) SIMPLE SALTS OF MERCURY WITH ORGANIC AND INORGANIC ACIDS. 